Labour leader Jeremy Corbyn has come under fresh attack for his handling of the party’s internal row over anti-Semitism, with one of his own MPs accusing him of “supporting and defending” extremists.

Ian Austin questioned Mr Corbyn’s suitability to lead the party, days after Dame Margaret Hodge admitted confronting him over the controversy over its rules on racism targeted at Jews.

Dudley North MP Mr Austin, the son of adoptive Jewish parents, said he was “deeply ashamed” of Labour for not fully adopting a widely-backed definition of anti-Semitism set out by the International Holocaust Remembrance Alliance (IHRA).

It comes as Marie van der Zyl, president of the Board of Deputies of British Jews, said Mr Corbyn was “leading the Labour Party into a dark place of ugly conspiracy theories” which had become a “home for overt anti-Semites and anti-Semitism”.

Meanwhile former front Labour front bencher Chris Leslie said he was “absolutely mortified” by the way the issue was being handled by the “higher command of the party”.

A party spokesman insisted Mr Corbyn, a veteran Palestinian rights activist, was a “militant opponent of anti-Semitism” and determined to tackle it.

Mr Austin spoke out after being told that like Dame Margaret, he is facing possible disciplinary action.

He admitted clashing with party chairman Ian Lavery over the IHRA definition but said it was just a “heated discussion”, and claims he “screamed abuse were false”.

He accused Mr Corbyn of introducing to Labour a more “extreme” brand of politics, telling BBC Radio 4’s The World This Weekend: “Somebody with views and history like his isn’t really suited to the leadership of a mainstream political party.”

Asked whether he was speaking out just because he did not want Mr Corbyn to lead the party, Mr Austin said: “He was never my choice to lead the Labour Party, that’s true, but what do people think? That I’m so worried about his plans to nationalise the railways or something that I would invent all this stuff?

“It’s actually the other way around. It’s because he has spent his entire time in politics on the extreme fringes of the Labour Party, supporting and defending all sorts of extremists and in some cases frankly, anti-Semites.”

He added that he had joined Labour to fight racism after he “grew up listening to my dad tell me how he’d escaped from the Holocaust and how his mum and sisters were murdered in Treblinka (concentration camp)”.

In an op-ed for Monday’s Guardian, Mr Austin, who has represented his West Midlands seat since 2005, added that “a minority of people” under Mr Corbyn’s leadership “go way beyond legitimate and passionately held views about the plight of the Palestinians and tip over into anti-Semitism”.

This is unprecedented. Every member of @UKLabour from @jeremycorbyn down should be ashamed.Antisemitism in our party has caused huge offence & distress to the Jewish community and we must listen to them and take it much more seriously. https://t.co/iPU5tjc21N

He added: “But for others it is much more fundamental, whether it is Ken Livingstone’s nonsense about Adolf Hitler, legitimising the myth that Jews were the chief financiers of the slave trade, or outrageous comparisons between the actions of Israel and the crimes of the Nazis.

“Jewish MPs – particularly women – have been subjected to the most horrendous abuse.”

Labour’s governing National Executive Committee (NEC) did not include within its new code of conduct the full definition of anti-Semitism – including illustrative examples – set out by the IHRA.

While the code explicitly endorses the IHRA’s working definition of anti-Semitism and lists of behaviours likely to be regarded as anti-Semitic word-for-word from the international organisation’s own document, it omits four examples:

– Accusing Jewish people of being more loyal to Israel than their home country;

– Claiming that Israel’s existence as a state is a racist endeavour;

– Requiring higher standards of behaviour from Israel than other nations; and

– Comparing contemporary Israeli policies to those of the Nazis.

Labour insisted the examples are they are covered in the new code.

Ms van der Zyl said the last few days had been “utterly shameful for the party”.

She added: “In 2018, Labour is not only a party with extravagant levels of tolerance for anti-Semitism but one which deliberately obstructs measures to counter hatred and punishes those who speak out against it.”

Speaking on Radio 4’s Westminster Hour, Mr Leslie said Mr Austin was “absolutely” right to voice his concerns.

“It’s to our collective shame that this is still dragging on month after month,” he said.

“It’s certainly not in my name and it’s clearly not in Ian Austin’s name either.”

A Labour spokesman said Mr Corbyn and the party were “fully committed to the support, defence and celebration of the Jewish community and its organisation”.

He added: “The NEC has concerns about one half of one of the IHRA’s 11 examples, which could be used to deny Palestinians, including Palestinian citizens of Israel and their supporters, their rights and freedoms to describe the discrimination and injustices they face in the language they deem appropriate.

“We understand the strong concerns raised in the Jewish community and are seeking to engage with communal organisations to build trust and confidence in our party.”